Process for producing amalgams to be used in dentistry



Patented May 5, 1931 PATENT OFFICE ERIK WILI-IELM FISCHER, or

STOCKHOLM, AND ERIK WILHELM J'zSON VIRGIN, DJ'URSHOLM, SWEDEN PROCESS FOR PRODUCING AMALGAMS TO BE USED IN DENTISTRY No Drawing. Application filed December 28, 1927, Serial No. 243,203, and. in Germany January 10, 1927.

This invention relates to an improved process for producing amalgams to be used in dentistry and more particularly to a specially prepared powder to be used in said process.

Tooth cement has hitherto been prepared by mixing a metal powder, for instance tin,

or more commonly an alloy such.v as silver and mation occurs so that the preparation of the cement has caused the dentist a considerable loss of time. By use of the common alloy powder the amalgamation continues after theamalgam has hardened which causes undesirable changes in the volume of the completed plug or filling.

This invention relates to the manufacture of a metal or alloy powder to be used for the production of amalgams for dentistry by means of which said disadvantages are avoided or substantially lessened. The improved results are obtained by providing the powder particles, in advance of use, with a thin superficial skin of mercury on their surface. This results in the V amalgamation being considerably facilitated and accelerated so that the use of such a prepared powder reduces the time required in mixing and kneading a quantity of powder in preparing fillings. The amalgamation will also be complete, or more nearly so, whereby when the amalgam is filled into the cavities no changes in volume of the plugs occur.

The treatment of the metal or alloy powder with mercury may suitably be carried out in the wet state and preferably in such a way that the powder is treated with finely divided mercury and a weakly c'orroding solution. The powder may for instance, preferably during the application of heat, be treated with a mercury salt such as mercuric chloride, and with an acid which dissolves tin but does not cause oxidation, for instance hydrochloric acid; Another way is to treat the powder, also while heated, with superficial skin only of the acid solution is poured off and the powder washed with water until the wash water no longer shows any acid reactlon. he powder 1s then drled at low heat and when dry, is ready for use,'although it may be kept for a considerable time before using without deterloratlon.

' We cla1m 1. An improved process for the production of silver alloy powder subsequently to be completely amalgamated in the production of dental fillings, consisting in treating the silver alloy particles with mercury in a quantity insufiicient to produce complete amalgamation.

2. A powdered substance for use in preparing dentalamalgam, comprising finely divided silver alloy particles treated with mercury to form a thin superficial skin only of amalgam thereon.

3; A powdered substance for use in preparing dental amalgam, comprising finely divided silver alloy particles and a relatively small amount of .mercury forming a thin amalgam on said particles.

4. The method of producing a material for use in preparing dental amalgam, which conslsts 1n sub ect1ng finely divided silver alloy powder to the action of a heated solution of mercuric chloride and hydrochloric acid so as to produce on the powder particles a thin superficialskin only of amalgam.

In testimony whereof we have hereunto set our hands.

ERIK WILHELM J: SON VIRGIN. ERIK .WILHELM FISCHER. 

